A new nanofabrication method is proposed for developing nano- composite polymer materials for biomedical sensing. These materials will be produced by controlled radical polymerization/copolymerization using cross-linkable self-assembled monolayers on gold colloidal nanoparticles as templates. The core-shell nano-structured materials are designed for making long-term implantable biosensors that may be used as "tattoo dyes" for noninvasive repetitive or real-time optical readout. The major objectives of this proposal are (1) to create nano-sized, affinity-sensing interfaces that are encapsulated within biocompatible polymer shells, and (2) to evaluate the potential of the resulting materials for optical sensing of glucose using UV-Vis, Raman, fluorescence and surface plasmon resonance spectroscopies. The polymer shells will minimize nonspecific bindings at the molecular recognition site of the sensing interface and consequently improve the longevity and biocompatibility of the resulting glucose sensor. The small size of the capsules and the large effective surface area of the sensing interface should allow for improvements in the selectivity, dynamic range, and mass transport (speed) in the affinity-based biosensor. Because the sensing elements are pre-organized on the surface of the nanoparticles, the structural homogeneity of the resulting sensing interface can be greatly improved. The nanophotonic properties of gold nanoparticles will be utilized as optical detection methods and for selective structural characterization of the encapsulated molecular recognition interface. Surface plasmon resonance spectroscopy and FT- IR will be used for rapid screening and establishing structure-property relationships of the desired sensing materials.